Impulse transmitter



A 1 il14, 1942. ,W AV 'R 2,279,360

IMPULSE TRANSMITTER 1 Filed Oct. 9, ,1940 2 sheets-sheet 1" INVEN 70/?,4. WEAVER ATTORNEY April Y 14, 1942.

WEAVER v 2,279,360 IMPULSE TRANSMITTER Filed Oct. 9, 1940 2Sheets-Sheet-Z INVENTOR A. WEAVER B v a ATTORNEY" Patented Apr. 14, 1942.1

IlvEPULSE TRAN SHUTTER Allan Weaver, Port Washington, N. Y., 'assignorto Bell Telephone Laboratories, Incorporated, New York, N. Y., acorporation of New York Application October 9, 1940, Serial No.360,414.,

4 Claims.

. spacing and independent of subscriber manipulation.

A feature of the invention is remote control of the speed of operationof the dial. In accordance with this feature the dial, instead of beingcontrolled by a local spring motor and mechanical governor arrangements,is driven by an alternating current of controlled frequency transmittedfrom the central office whereby uniform speed is attained.

Another feature of the invention is the use of the two conductors of thetelephone line in parallel for driving the dial and the two conductorsof the line in series for transmitting the signals.

Another feature of the invention is an arrangement whereby power istransmitted from the central office for operating a substation dialwhile the dial is simultaneously sending signals to the central ofliceover the same conductors.

The drawings consist of two sheets containing four figures.

Fig. 1 is a schematic diagram showing the mechanical arrangements of asubstation dial;

Fig. 2 is a cross-sectional view of the same taken on the line 2-2 ofFig. 1;

Fig, 3 is a schematic circuit diagram illustrating the manner in whichthe substation dial operates; and

Fig. 4 is a perspective view of a single dial key illustrating thecamming and locking arrangements.

Considering first the manner of operation as illustrated by Fig. 3, itwill be noted that a pair of dot-and-dash lines are used to indicate thecircuit arrrangements at the central office and at the substation. Thecircuit to the left of the first broken line shows the central ofiicearrangements. The circuit between the two broken lines shows the linecircuit and the circuit to the right of the second broken line shows thesubstation arrangement. At the central oi ice a source I representsalternating current of controlled frequency. By means of a transformerhaving a primary winding 2 and two secondary windings 3 and 4, thealternating current is transmitted over the lines 5 and 6 and thence inparallel through the condensers I and 8 to the winding 9 of a vibratorymotor II]. The armature II of the motor is so constructed and arrangedthat it will cause a vibratory movement of the the latch I2 insynchronism with the alternating current from source I'. When a buttonhas been pressed, as will be hereinafter described, the latch I2 isallowed to come into engagement with the ratchet I3 until the stop I4engages a depressed key and stops the movement. During this time theimpulse wheel I5 is rotated and the spring It in cooperation with thespring I! sends impulses over the line to operate the relay I3 at thecentral office. It will be made clear hereinafter how the springs I9 and2l| which normally shunt the springs I6 and I! are caused to open duringthe time over which the latch i2 engages the ratchet I3 so that impulsesin the form of short openings of the line circuit are sent to operatethe relay I8 at this time. the stop member I4 engages a depressed key,the latch I2 is moved from engagement with the ratchet I3 and thesprings I9 and 20 come into the position shown so that the action ofsprings I 6 and I1 during the return movement of the member I5 isineffective.

It should be'noted that circuit arrangements for establishing theconnection at the central office, as shown, only during the dialingperiod, as indicated by the dotted portions of the line conductors tothe left of the first dot and dash line, will be provided but since sucharrangements form no part of the present invention they are notillustrated in these drawings.

The action of the dial is more fully illustrated in Figs. 1, 2 and 4. InFig. 1 the armature II of the vibratory motor II] only is illustrated..The latch I2 is shown held away from engagement with ratchet I3 by apin 2|. Retaining pawl 22 is likewise held out of engagement with theratchet I3 by a pin 23. The springs I9 and 20 illustrated in Fig. 3 asbeing controlled by the latch I2 are illustrated in Fig. 1 as beingcontrolled by a projection 24 from the plate 25. The action of both isthe same.

When dialing is to take place, then a key such as that shown in Fig. 4is depressed. This key has on its stem 26 a latching projection 21 and acamming surface 28. Upon the depression of the key against the pressureof a spring 29, the camming surface 28 operates to move the plate 25 ashort distance in a clockwise direction against the pressure of a returnspring 30. Pins 2I and 23 are fixed to plate 25 so that the movement ofthese pins allows both the latch I2 and the retaining pawl 22 to engagethe ratchet I3. The ratchet I3 will now be driven at a uniform rate in aclockwise direction.

When

When the key or stem 26 was depressed then a latch 3| was rotated in acounter-clockwise direction so that its upper end moved over the member21 of the key and held the key in its downwardly depressed position. Asthe ratchet I3 is moved in a clockwise direction, the stop member I4moves until it engages the lower portion of the latch member 3|whereupon this latch member is rotated into the position shown in Fig. 2and the key on the stem 26 is allowed to restore to its normal position.Upon this movement of the key, the plate 25 is returned under thetension of spring 30 to its normal position whereupon pins 2| and 23disengage the latch I2 and the retaining pawl I4 from engagement withthe ratchet I3. Thereupon the impulse wheel I5 and the ratchet I3 arereturned to normal under the driving force of spring 32. In the normalposition the stop member I4 will engage a cooperating stop member 33 andthe dial will remain in the position illustrated until another key isdepressed.

It should be noted that the invention here. is illustrated practicallyin a schematic form which may be altered in many ways in building acommercial piece of apparatus without departing from the spirit. of theinvention.

What. is claimed is:

1. In a signaling system, a two-conductor line terminating at one end ina signal receiving device and at. the other end in a signal transmittingdevice, a source of alternating current at the receiving end of saidline and a synchronous alternating' current motor at the transmittingendof said line, said source of current being connected in a groundreturn circuit to said motor over the two conductors of said line inparallel, and means for driving said signal transmitting device by saidmotor, said device transmitting signals consisting of interruptions of acircuit including the two conductors of said line in series.

3. In a signaling system, a two-conductor line terminating at one end ina signal receiving device and at the other end in a signal transmittingdevice, a source of alternating current at the receiving end of the lineand a synchronous alternating current motor at the transmitting end ofthe said line, a circuit for linking said motor to said source ofcurrent, including the two conductors of said line in parallel, meansfor variably setting said transmitting device for the transmission ofvarious signals, andmeans responsive to the setting of said device foroperatively associating said device with said motor whereby said deviceis driven by said motor through a distance corresponding to the settingof said device.

4. In a signaling system, a two-conductor line terminating at one end ina signal receiving device and at. the other end in a signal transmittingdevice, a source of alternating current at the receiving end of the saidline and a synchronous alternating current motor at the transmitting endof said line, a circuit for linking said motor to said source of currentincluding the two conductors. of said line in, parallel, means forvariably setting said transmitting device for the transmission ofsignals, means responsive to the setting of said device. for operativelyassociating said device with said motor whereby said device is driven bysaid motor through a distance corresponding to the setting of saiddevice, a pair of contacts controlled by said device for interrupting asignaling circuit including the two conductors of said line in seriesand another pair of contacts for shunting said first pair of contactsatv all times excepting while said device is being driven by said motor.

ALLAN WEAVER.

